1. Field of the Invention
This invention relates to a new pharmaceutical composition for treating leukemia, more specifically, for treating nonlymphatic leukemia, such as acute chronic granulocytic and monocytic leukemia without adverse side effects.
2. Description of Prior Art
Nemerous antileukemia drugs have been investigated but so far, there is no single drug that is effective and safe. As discussed in U.S. Pat. No. 3,497,593, an alkaloid from Tylophora plant is said to have antitumor activity against mouse leukemia (L-1210). U.S. Pat. No. 3,928,584 disclosed an organic composition derived from tree saps and is said to have activity against mouse leukemia P-388. Also U.S. Pat. No. 4,431,639 disclosed that an extract of Rhisoma Stractylis promotes the production of lumphocytes in the circulating blood, consequently eliminating cancer growth.
Harringtonine and Homoharringtonine, hereinafter referred to as HH, has been known to be effective against acute chronic granulocytic and monocytic leukemia (Journal of Chinese Internal Medicine 3:162-164, 1978). However, it has severe toxicity causing damage to heart and hematopoietic organs. The results of experiments in animals, such as mice, rabbits and dogs, indicate that most of them die from cardiotoxicity after receiving the drug. Therefore, there is a need to improve the HH drug for safe use against leukemia. This drug is of special importance in that all known antileukemia drugs are effective against lymphatic leukemia and there are no effective drugs for treating nonlymphatic leukemia. The pharmaseutical composition in accordance with the present invention treats nonlymphatic leukemia, especially acute chronic granulocytic and monocytic leukemia, without side effect.